Protein kinases are dedicated to transfer phosphate group from ATP to one or more OH groups of a substrate protein. In this process they play catalytic role in phosphorylation reactions in living cells. Phosphorylation is the mode of information transmission on biomolecular level and can regulate the activity of certain proteins, which are tipically other protein kinases. There are about 1000 protein kinases known. There are receptor protein kinases, which are located in cellular membranes and non-receptor protein kinases, which are located in the cell plasm. We speak about tyrosine protein kinases when one can phosphorylate tyrosine OH and serine-threonine protein kinases when one can phosphorylate serine or threonine OH group. CDKs are non-receptor serine-threonine protein kinases that require cycline for their activity (Cycline Dependent protein Kinases).
One of the most important and fundamental processes in biology is the division of cells during the cell cycle. This process ensures the controlled production of subsequent generations of cells with defined biological function. It is a highly regulated phenomenon and responds to a diverse set of cellular signals both within the cell and from external sources. Cyclin dependent kinases (CDKs) play a key role in regulating the cell cycle machinery. These complexes consist of two components: a catalytic subunit (the kinase) and a regulatory subunit (the cyclin). To date, thirteen kinase subunits have been identified in humans (Chen et al., Biochem. Biophys. Res. Commun. 2007, 354, 735-40; S. Mani et al., Exp. Opin. Invest. Drugs 2000, 9(8), 1849-1870, J. C. Sergere et al., Biochem. Biophys. Res. Commun. 2000, 276, 271-277, D. Hu et al, J. Biochem. Chem. 2003, 278(10), 8623-8629).
It is known that CDKs play a role in the regulation of cellular proliferation. Therefore, CDK inhibitors could be useful in the treatment of cell proliferative disorders such as cancer, neuro-fibromatosis, psoriasis, fungal infections, endotoxic shock, transplantation rejection, vascular smooth cell proliferation associated with artherosclerosis, pulmonary fibrosis, arthritis, glomerulonephritis and post-surgical stenosis and restenosis (U.S. Pat. No. 6,114,365).
CDKs are also known to play a role in apoptosis. Therefore CDK inhibitors could be useful in the treatment of cancer; autoimmune diseases, for example systemic lupus, erythematosus, autoimmune mediated glomerulonephritis, rheumatoid arthritis, psoriasis, inflammatory bowel disease, and autoimmune diabetes; neurodegenerative diseases for example Alzheimer's disease, AIDS-related dementia, Parkinson's disease, amyotrophic lateral sclerosis, retinitis pigmentosa, spinal muscular atrophy and cerebellar degeneration; myelodysplastic syndromes, aplastic anemia, ischemic injury associated with myocardial infarctions, stroke and reperfusion injury, arrhythmia, atherosclerosis, toxin-induced or alcohol related liver diseases; hematological diseases, for example, chronic anemia and aplastic anemia; degenerative diseases of the musculoskeletal system, for example, osteoporosis and arthritis, cystic fibrosis, multiple sclerosis, kidney diseases and cancer pain and for the treatment of cardiovascular diseases (U.S. Pat. No. 6,107,305 and WO 02/100401).
Further it is known that CDK inhibitors could be used for the treatment of virally induced infectious diseases, such as EBV, HBV, HCV and HIV (WO 02/100401). Recently, it was described, that HIV-1 replication could be affected by inhibiting CDKs (C. de la Fuenta, Current HIV research, 2003, 1(2), 131-152; Y. K. Kim et al., Molecular and Cellular Biology, 2002, 22(13), 4622-4637). Especially CDK9 is reported to be essential for the HIV-1 replication (H. S. Mancebo et al, Genes Dev. 1997, 11(20): 2633-44, O. Flores et al., Proc. Natl. Acad. Sci. USA. 1999, 96(13):7208-13). CDK9 is also involved in the development of pain: both cyclin T1 and CDK9 stimulate the basal promoter activity of TNFa, a pro-inflammatory cytokine and pain mediator that controls expression of inflammatory genetic networks. For mediation of cellular TNF receptor responses, the nuclear factor-KB (NFKB) pathway is crucial. TNFa triggers its recruitment to cytokine genes while NFKB interacts with the p-TEFb complex for stimulation of gene transcription (Barboric M. et al., NFKB Binds P-TEFb to Stimulate Transcriptional Elongation by RNA Polymerase II. Molecular Cell, 2001, Vol. 8, 327-337).
Additionally, it has been shown that CDK9 is a binding partner of TRAF2, a member of the TNFa receptor complex (MacLachlan T. K. et al., Binding of CDK9 to TRAF2. J. Cell Biochem., 1998, 71(4), 467-478), while GP130, a subunit of the pro-inflammatory IL6 receptor complex has recently been identified as another potential binding partner of CDK9 (Falco G. D. et al., CDK9, a member of the cdc2-like family of kinases, binds to gp130, the receptor of the IL-6 family of cytokines. Oncogene, 2002, 21(49), 7464-7470). As a key player in TNFa and interleukin signaling as well as NFKB mediated expression of several genes (e.g. cytokines as pain mediators), CDK9 can thus be considered as a central target for the treatment of inflammatory pain.
There also exists a strong link between CDK9 and caridac hypertrophy (reviewed in Sano & Schneider, Circulation Research, 2004, 95, 867) and inhibitors of CDK9 are expected to be effective in the treatment of cardiovascular diseases, such as caridac hypertrophy.
Most of the known CDK inhibitors, such as olomoucine, roscovitine (CYC202), purvalanols, indolinones, paullones and 7-hydroxy-staurosporine are focusing on the inhibiton of CDK1 and CDK2 with the goal of antitumor activity (Current Opinion in Pharmacalogy, 2003, 3, 1-9). A summary of the known CDK inhibitors is given by M. Huwe et al. (A. Huwe et al., Angew Chem Int Ed Engl. 2003; 42(19): 2122-38). Flavopiridol is described as a low-molecular, but unselective inhibitor of CDKs, including CDK9 (W. Filgueira de Azevedo et al., Biochem. and Biophys. Res. Commun. 2002, 293(1), 566-571). Other compounds that were shown to inhibit CDKs are staurosporine, fascaplysin and hymenialdisine.
The use of 4-aminopyrimidine derivatives as neuroprotective agents is described in WO 02/12198. These compounds generally contain as a basic residue a substituted amine in para position of the anilino part of the molecule and it is stated that these compounds did not inhibit MEK1/2 kinase activity in P19 neurons. U.S. Pat. No. 3,950,525 describes the use of 4-amino-6-aryl-pyrimidines as platelet aggregation inhibitors and bronchodilators. U.S. Pat. No. 3,478,030 describes the synthesis of benzamide substituted anilino aminopyrimidine derivatives. These compounds are used as potent dilators of coronary arteries. WO 02/79197 describes the use of aryl-substituted 2-aminopyrimidine derivatives as protein kinase inhibitors, for example as inhibitor of JNK, GSK-3, Src, Lck or CDK2. Certain 4,6-disubstituted aminopyrimidines are described in WO 05/026129. WO 05/026129 describes derivatives which are useful as pharmaceutically active agents, especially for the prophylaxis and/or treatment of infectious diseases, including opportunistic diseases, prion diseases, immunological diseases, autoimmune diseases, bipolar and clinical disorders, cardiovascular diseases, cell proliferative diseases, diabetes, inflammation, transplant rejections, erectile dysfunction, neurodegenerative diseases and stroke. However, the 4,6-disubstituted aminopyrimidines described in WO 05/026129 are structurally different to those described in the present application.
WO 06/125616 describes the use of CDK inhibitors, including CDK9 inhibitors, such as the 4,6-disubstituted aminopyrimidines disclosed in WO 05/026129, for the treatment of pain and inflammatory diseases.
There is a high unmet medical need to develop CDK inhibitors, useful in treating various medical conditions or diseases associated with CDK activation, in particular those conditions or diseases concerning CDK9 kinase activity, which is associated with cell proliferative disease, infectious disease, pain, cardiovascular disease and inflammation.
Compounds having similar structure are claimed in WO 2005/026129, WO 2008/132138 and US 2008/0275063 but there is no alkylene chain between the methylenesulfone or methylenesulfonamide group and the aryl moiety in the disclosed compounds.
In one aspect of the present invention, the compounds of the present invention or pharmaceutically acceptable salts and solvates thereof can be used as an inhibitor for a protein kinase, preferably as an inhibitor for a cellular protein kinase.
In a particular embodiment of these aspects said cellular protein kinase is a cyclin-dependent protein kinase (CDK). The cyclin-dependent protein kinase can be selected from the group comprising: CDK1, CDK2, CDK3, CDK4, CDK5, CDK6, CDK7, CDK8, CDK9, CDK10, CDK11, CDK12, CDK13, CrkRS (Crk7, CDC2-related protein kinase 7), CDKL1 (cyclin-dependent kinase-like 1); KKIALRE, CDKL2 (cyclin-dependent kinase-like 2), KKIAMRE, CDKL3 (cyclin-dependent kinase-like 3), NKIAMRE, CDKL4, similar to cyclin-dependent kinase-like 1, CDC2L1 (cell division cycle 2-like 1), PITSLRE B, CDC2L1 (cell division cycle 2-like 1), PITSLRE A, CDC2L5 (cell division cycle 2-like 5), PCTK1 (PCTAIRE protein kinase 1), PCTK2 (PCTAIRE protein kinase 2), PCTK3 (PCTAIRE protein kinase 3) or PFTK1 (PFTAIRE protein kinase 1). In particular such embodiments, said cyclin-dependent protein kinase is CDK9.
Although only CDK9 inhibitory effect is proved, inhibition of other CDKs can be expected as there are close relationship amongst cyclin dependent kinases. It can be assumed by a skilled person that other kinases also can be inhibited by the compounds of this invention because of the highly conserved ATP binding site which is presented in all protein kinases. Vast majority of small molecule inhibitors block kinases by binding to the ATP binding site, so these inhibitors have a general inhibitory effect on protein kinases (including CDKs, too, of course).
According to the current state of the art multiple kinase inhibitors are considered to be better to develop in contrast to selective ones, as they could block alternative signaling pathways and this way they show enchanced cellular and in vivo effect. However, selective inhibition of CDK9 can also be fruitful especially in the treatment of HIV infections. Unexpected side effect can be avoided by inhibiting only one key kinase.
With respect to the highly conserved ATP binding site which is presented in all protein kinases it is a well-based assumption that the compounds according to the invention have a general protein kinase inhibitory, especially CDK inhibitory effect.